Question

4x2-9x-100 (by quadratic equation)

Answer 1

a = 4
b = -9
c = -100



Discriminant = b^2 - 4ac

=> ( - 9 )² - 4(-100 × 4)
=> 81 + 1600
=> 1681



Applying quadratic equation,


$x = \frac{ - ( - 9) + \sqrt{1681} }{2(4)} \: \: \: \: or \: \: \: \: \: x = \frac{ - ( - 9) - \sqrt{1681} }{2(4y} \\ \\ \\ \\ => x = \frac{9 + 41}{8} \: \: \: \: or \: \: \: \: x = \frac{9 - 41}{8} \\ \\ \\ => x = \frac{25}{4} \: \: \: or \: \: \: \: x = - 4$

Answer 2

4x² - 9x - 100

=> 4x² - 25x + 16x - 100

=> x(4x - 25) + 4(4x - 25)

=> (x + 4) (4x - 25)